Hi Jeff,
On Wed, Aug 01, 2018 at 07:03:54AM -0400, Jeff Layton wrote:
> On Tue, 2018-07-31 at 14:10 -0700, Mark Fasheh wrote:
> > /proc/locks does not always print the correct inode number/device pair.
> > Update lock_get_status() to use vfs_map_unique_ino_dev() to get the real,
> > unique values for userspace.
> >
> > Signed-off-by: Mark Fasheh <mfasheh@xxxxxxx>
> > ---
> > fs/locks.c | 12 +++++++++---
> > 1 file changed, 9 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/locks.c b/fs/locks.c
> > index db7b6917d9c5..3a012df87fd8 100644
> > --- a/fs/locks.c
> > +++ b/fs/locks.c
> > @@ -2621,6 +2621,7 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
> > loff_t id, char *pfx)
> > {
> > struct inode *inode = NULL;
> > + struct dentry *dentry;
> > unsigned int fl_pid;
> > struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
> >
> > @@ -2633,8 +2634,10 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
> > if (fl_pid == 0)
> > return;
> >
> > - if (fl->fl_file != NULL)
> > + if (fl->fl_file != NULL) {
> > inode = locks_inode(fl->fl_file);
> > + dentry = file_dentry(fl->fl_file);
> > + }
> >
> > seq_printf(f, "%lld:%s ", id, pfx);
> > if (IS_POSIX(fl)) {
> > @@ -2681,10 +2684,13 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
> > : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
> > }
> > if (inode) {
> > + __u64 ino;
> > + dev_t dev;
> > +
> > + vfs_map_unique_ino_dev(dentry, &ino, &dev);
>
> This code is under a spinlock (blocked_locks_lock or ctx->flc_lock). I
> don't think it'll be ok to call ->getattr while holding a spinlock.
Hmm, indeed it does call under spinlock. I'll hve to rethink how to approach
this in fs/locks.c
Thanks,
--Mark
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